Oh, I see. No. You can create and use multisample textures of any number of samples under-the-hood independent of how many samples per pixel you allocate for your system framebuffer.

One small point with that. If you want to blit your multisample texture to your system framebuffer that is also multisampled, they must have the same number of samples. If the system framebuffer is not multisampled, then you can use any sample count you want.

This came up at one point because drivers often have a way to let users force multisampling on applications. And this usually manifests as forcing multisampling on the back buffer, thus breaking the blit from the internal FBO to the back buffer.